Imo it should have been:
- Vanilla + DB & HoW as Launch game
- TTK as first main DLC for between £30 and 40 (i.e. not full game pricing)
- ROI as the next proper DLC for between £20 and 30.
- Supported from the start with cosmetic only micro transactions + balanced so that the gear could also be earned in game (costing time) - basically what we have now with the silver dust kiosk* but existing from the start.
If they had taken this approach I think the game would have been better received, specifically at launch (main criticism was lack of content). They could have still time gated TDB and HoW but made them part of the vanilla package.
*For those who haven't seen it you can now buy everything available from Eververse for silver dust. You get three packages weekly which contain items (RNG) from EV which, if not wanted, can be turned into Silver Dust (IIRC you can earn 15 SD per week this way - items cost between 5 and 35 SD). You can also buy silver outright which can be used to buy the same packages.